Eletromechanical brake actuator

ABSTRACT

The invention relates to an electromechanical brake actuator ( 1 ) for a rail vehicle brake, comprising an actuator housing ( 2 ) and electronic components, such as for example power electronics, control electronics or sensor technology. At least some of the electronics components are placed in a separate electronics housing ( 6 ), which is detachably connected to the actuator housing ( 2 ). The invention is characterised in that the connection has at least one vibration damping element, located between a flange ( 18 ) of the actuator housing ( 2 ) and a flange ( 16 ) of the electronics housing ( 6 ) and that with the exception of the flange connection ( 12 ), a clear gap ( 30 ) exists between the electronics housing ( 6 ) and the actuator housing ( 2 ).

STATE OF THE ART

[0001] The invention relates to an electromechanical brake actuator for a rail vehicle brake containing an actuator housing as well as electronic components, such as power electronics, control electronics or an electronic sensor system, at least some of the electronic components being accommodated in a separate electronic system housing which is detachably connected with the actuator housing, according to the preamble of Claim 1. A brake actuator of this type is known, for example, from U.S. Patent Document U.S. Pat. No. 5,692,586.

[0002] Currently, three wheel brake systems are essentially used in the rail vehicle field: Pneumatic or electropneumatic brake systems, hydraulic or electrohydraulic brake systems as well as mechanical or electromechanical brake systems. In this case, the wheel brake system may be constructed as an active or passive brake system, depending on whether the force of a brake actuator has to be applied for braking (active brake system) or for releasing the brake (passive brake system). In the event of operating disturbances, in the case of pneumatic systems, an energy accumulation takes place in compressed-air reservoirs; in the case of hydraulic systems, this energy accumulation takes place in hydraulic reservoirs; and, in the case of electromechanical systems, it takes place in the form of preloaded springs.

[0003] In the case of electromechanical brake actuators, an electric-motor drive is used as the service brake device, which can be controlled by control or power electronics to carry out slip-controlled or load-corrected brakings. When the brake actuator together with the electronic components assigned to it is to be fastened as an integrated brake module to the bogie, the problem arises that shock or vibration stress caused, for example, by rail joints or switching shocks may result in damage to the electronic components. Furthermore, particularly at high ambient temperatures, the electronic components may be subjected to a temperature-caused stress which leads to disturbances or to total failure.

[0004] In contrast, it is an object of the present invention to further develop an electromechanical brake actuator of the initially mentioned type such that its electronic or electrical components have a greater reliability and a longer service life.

[0005] According to the invention, this object is achieved by means of the characterizing features of Claim 1.

ADVANTAGES OF THE INVENTION

[0006] As a result of the flexible and vibration-damping flange connection between the electronic system housing and the actuator housing, the electronic components are uncoupled with respect to vibrations from the structure born noise of the actuator housing. In particular, the natural frequencies of the electronic unit are thereby displaced toward lower values, whereby higher-frequency excitations can no longer cause sympathetic vibrations. Furthermore, lower vibration amplitudes are obtained because of the energy loss in the damping elements.

[0007] As a result of the fact that, with the exception of the flange connection, a clearance exists between the electronic system housing and the actuator housing, the presence of an insulating air layer or of a cooling air flow is permitted between the actuator housing heated by the operation of the electric drive and the electronic system housing, so that the thermal stress is reduced which acts upon the electronic components.

[0008] As a result of the measures indicated in the subclaims, advantageous further developments and improvements of the electromechanical brake actuator indicated in Claim 1 are possible.

[0009] The vibration-damping element is preferably formed by a rubber ring which is arranged between the flange of the actuator housing and a flange of the electronic system housing. As a result, the rubber ring is situated in the flux of force between the actuator housing and the electronic system housing and uncouples the latter form the actuator housing.

[0010] According to a particularly preferred measure, at least some of the electronic components are arranged on at least one printed circuit board which, inside the electronic system housing, is accommodated by at least one other vibration-damping element. This results in an additional vibration uncoupling of the electronic system components from the structure-borne sound guiding actuator housing or also from the electronic system housing.

[0011] A plug, which is assigned to the electronic system housing or to the actuator housing or a bush assigned to the electronic system housing or the actuator housing is fastened to the actuator housing or to the electronic system housing, also in a vibration-damped manner. As a result, no stiff vibration-transmitting bridges can be created in the plug/bush area.

DRAWINGS

[0012] An embodiment of the invention is illustrated in the drawing and will be explained in detail in the following. The single FIGURE is a cross-sectional view of a brake actuator according to a preferred embodiment of the invention.

DESCRIPTION OF THE EMBODIMENT

[0013] The preferred embodiment of an electromechanical brake actuator of a rail vehicle which, as a whole, has the reference number 1 in FIG. 1, contains an electric drive, such as an electric servo motor, which, for reasons of scale, is not shown and which is accommodated in an actuator housing 2. The servo motor causes the rotation of a brake spindle, which is also not shown and acts upon a power converter which converts the rotating movements of the brake spindle into a brake application movement of brake linings in the direction of an axle-mounted brake disk. The actuator housing 2 is held on a bogie of the rail vehicle in the area of the axle-mounted brake disk, which bogie is exposed to vibrations.

[0014] The brake actuator 1 comprises electrical or electronic components, such as an electronic control and power system for controlling the servo motor. Of these electrical or electronic components, at least some are arranged on a printed circuit board 4 which is held within a separate electronic system housing 6 consisting of two half-shells. Toward all sides, the printed circuit board 4 is spaced away from a housing wall 8 of the electronic system housing 6 and is connected with that wall 8 only by pin-shaped damping elements 10 which preferably consist of rubber.

[0015] The electronic housing 6 is preferably detachably fastened by means of a flange connection 12 on the bottom 20 of the actuator housing 2. For this purpose, an upward-pulled surrounding flange 16 is molded to the upper housing wall 14 of the electronic housing 6, which flange 16 is situated opposite a respective complementary flange 18 of the actuator housing 2. A flange opening 24 receiving a plug/bush connection 22 extends within the two flanges 16, 18, through which flange opening 24, mutually assigned electrical cables of the servo motor and of the electronic control and power system accommodated by the printed circuit board 4 are detachably connected with one another. The plug 26 is fastened to the actuator housing 2 in a vibration-damped manner; the bush 28 is connected with the printed circuit board 4, which is vibration-damped anyhow, and projects so far away from the latter in the upward direction that the plug 26 engages in the bush 28 when the electronic system housing 6 is flanged to the actuator housing 2.

[0016] With the exception of the flange connection 12, a clearance 30 exists between the upper housing wall 14 of the electronic system housing 6 and the bottom 20 of the actuator housing 2, in which clearance 30 ambient air can circulate. A damping element 32 consisting, for example, of an elastic rubber ring is arranged between the faces of the two flanges 16, 18 and is held there by suitable measures. The damping element 32 is therefore included in the flux of force between the actuator housing 2 and the electronic system housing 6. A bridging of the elastic damping element 32 by stiff or rigid connection elements is preferably not provided.

[0017] On its bottom wall 34 pointing away from actuator housing 2, the electronic system housing 6 is provided with cooling ribs 36 and, in addition, is arranged in an area of the actuator housing 2 which is at least partially exposed to an air current caused by the operation of the rail vehicle.

[0018] List of Reference Numbers

[0019]1 Brake actuator

[0020]2 actuator housing

[0021]4 printed circuit board

[0022]6 electronic system housing

[0023]8 housing wall

[0024]10 damping element

[0025]12 flange connection

[0026]14 upper housing wall

[0027]16 flange electronic system housing

[0028]18 flange actuator housing

[0029]20 actuator housing bottom

[0030]22 plug/bush connection

[0031]24 flange opening

[0032]26 plug

[0033]28 bush

[0034]30 clearance

[0035]32 damping element

[0036]34 electronic system housing bottom

[0037]36 cooling ribs. 

1. Electromechanical brake actuator (1) for a rail vehicle brake containing an actuator housing (2) as well as electronic components, such as power electronics, control electronics or an electronic sensor system, at least some of the electronic components being accommodated in a separate electronic system housing which is detachably connected with the actuator housing, characterized in that the connection has at least one vibration-damped element (32) which is arranged between a flange (18) of the actuator housing (2) and a flange (16) of the electronic housing (6), and in that, with the exception of the flange connection (12), a clearance (30) exists between the electronic system housing (6) and the actuator housing (2).
 2. Electromechanical brake actuator according to claim 1, characterized in that at least some of the electronic components are arranged on at least one printed circuit board (4) which, within the electronic system housing (6), is accommodated by at least one other vibration-damping element (10).
 3. Electromechanical brake actuator according to claim 1 or 2, characterized in that the vibration-damping elements (10, 32) preferably are rubber or spring elements.
 4. Electromechanical brake actuator according to claim 3, characterized in that the vibration-damping element is formed by means of a rubber ring (32) between the flange (18) of the actuator housing (2) and the flange (16) of the electronic system housing (6).
 5. Electromechanical brake actuator according to claim 4, characterized in that a plug/bush connection (22) is arranged in a flange opening (24).
 6. Electromechanical brake actuator according to claim 5, characterized in that a plug (26) assigned to the electronic system housing (6) or to the actuator housing (2) or a bush assigned to the electronic system housing (6) or the actuator housing (2) is fastened also in a vibration-damper manner to the actuator housing (2) or to the electronic system housing (6).
 7. Electromechanical brake actuator according to one of the preceding claims, characterized in that the electronic system housing (6) is equipped with cooling ribs (36) at least on the side pointing away from the actuator housing (2).
 8. Electromechanical brake actuator according to one of the preceding claims, characterized in that the electronic system housing (6) is arranged in an area of the actuator housing (2) which is at least partially exposed to an air current caused by the operation of the rail vehicle. 